Chop saws comprise a cutting unit pivotally mounted on a base assembly. The cutting unit is located above the base and can pivot between a high position where it is located further most away from the base assembly to a low position where a circular saw blade, which is mounted on the cutting unit and which is capable of being rotationally driven by a motor located within the cutting unit, can engage with a work piece located on the base assembly. A spring biases the cutting unit to its uppermost position.
Such chop saws can have a sliding feature wherein the cutting unit, in addition to be able to perform a pivotal or chopping movement, can slide linearly across the base assembly to perform a slide cut. Furthermore, these types of saw can include mechanisms by which they are able to perform miter and/or bevel cuts on workpieces located on the base assembly. A saw which is capable of performing chop, sliding, bevel and miter cuts is known as a sliding compound miter saw.
All of these types of saw usually comprise guards which surround at least a part of the edge of the saw blade in order to prevent the operator from touching the cutting edge. Typically, such saws comprise a fixed guard which surrounds the cutting edge of the top half of the cutting blade and a pivotal guard which is capable of surrounding the cutting edge of the lower half of the cutting blade. The pivotal guard is capable of being pivoted from a first position where it surrounds the cutting edge of the lower half of the cutting blade to a retracted position where the cutting edge of the lower half of the cutting blade is exposed so that the cutting blade can be used to cut a work piece. The purpose of the pivotal guard is to enable the cutting edge of the lower half of the circular saw blade to be surrounded when the saw blade is not being used to provide protection to the operator while allowing the cutting edge of the lower half of the circular saw blade to be exposed when it is required to perform the cutting function.
There are numerous mechanisms by which the pivotal guard can be pivoted from its first position to a retracted position.
EP0242733 discloses a sliding compound miter saw which comprises a base having a rotatable table mounted within it. The rotatable table, in conjunction with a fence fixed to the base, enables the sliding compound miter saw to perform miter cuts. Connected to the rear of the table is a bevel mount which is able to pivot about a horizontal axis in relation to the table. The pivotal movement of the bevel mount in relation to the table enables the sliding compound miter saw to perform bevel cuts.
Pivotally mounted onto the bevel mount are two guide rods which are capable of pivoting about an axis, parallel to the axis of rotation of the saw blade of the saw, between an upper and lower position. This enables the saw to perform chop cuts.
Slidingly mounted on the guide rods is a cutting unit, which comprises a motor for rotationally driving the circular saw blade mounted on a drive spindle on the motor unit. The sliding movement of the motor unit along the guide rods enables the saw to perform sliding cuts.
Rigidly mounted to the cutting unit is a fixed guard which surrounds the cutting edge of the top half of the cutting blade. Pivotally mounted to the cutting unit is a pivotal guard which can pivot between a first position where it surrounds the cutting edge of the lower half of the cutting blade and a retracted position where the cutting edge of the lower half of the blade is exposed for use in cutting.
The pivotal guard is pivoted between its two positions using a switch mounted on the handle which is mechanically linked to the pivotal guard. In use, the switch is depressed retracting the pivotal guard and then the saw can be operated.